The Controlled-source Audio-frequency Magnetotellurics (CSAMT/AMT) method tested in the search for deep Fe-Skarn mineralization at Kimmeria, Xanthi, N. Greece

The CSAMT/AMT method was used for the first time in Greece by HSGME and was field-tested on the ongoing exploration carried out at the Kimmeria Public Mining Area. The skarn mineralization (Fe+Cu±W±Bi) is related to the Xanthi pluton and develops along the contact of the granodiorite and the adjacent metamorphic rocks. In the magnetotelluric methods (MT), electromagnetic fields are utilized to investigate the electrical properties of the earth and to determine resistivity structures. The electromagnetic fields can be of natural origin (AMT) or created by artificial sources (CSAMT). The AMT fields result from lightning discharges (1 Hz-10 kHz) and the CSAMT far field is created by alternating current run through a grounded cable at frequencies between 0.25 Hz-8 kHz at a large distance (6.5 Km) from the investigation area. The CSAMT survey was conducted in the eastern part, targeting a skarn zone with Fe- Cu mineralization in the vicinity of the old mine. The results show a highly conductive body with resistivity values of 5-20 Ohm*m, dipping under the granodiorite, at a depth of 200 m, which is probably interpreted as a mineralized skarn zone. The investigation depth of the method reached 800 m. The AMT survey conducted over a skarn zone in the western sector of the area showed a good agreement with IP data with a succession of conductive layers from 40-200 m depth with resistivities of 10-25 Ohm.m and probable correlation to the mineralized zones. The methods confirmed their advantages in terms of investigating at depth and resolution.